Waveguide-to-microstrip transition for mmwave and MMIC applications

Abstract

A waveguide-to-microstrip transition package (30) for processing electromagnetic wave signals includes a waveguide (32) for directing the signals to the input of the waveguide (32). A substrate (34) overlaps the input of the waveguide (32) to form a hermetic seal. A metallized probe (36) conducts the signals to a microstrip line (40) and is patterned upon the substrate (34). The transition (30) also includes an iris (48) formed from a metallized pattern on the opposite side of the substrate (34) from the probe (36). The special design of the probe (36), the structure of the iris (48) and the wave guide cavity (46) above the probe (36) allow impedance matching and efficient signal transfer from waveguide (32) to microstrip line (40) or from microstrip line (40) to waveguide (32).

It is claimed: 
     
       1. A waveguide-to-microstrip transition for processing electromagnetic wave signals comprising: a waveguide for directing said signals to a waveguide input;   a cover for forming at least a portion of a cavity over said waveguide input, said cover providing both a backshort and a seal for said transition;   a first substrate for completely covering said waveguide input so as to form a hermetic seal over said waveguide input, said first substrate being substantially disposed in said cavity;   a first probe on said first substrate for conducting said signals to a microstrip line, and overlying said waveguide input; and   a second substrate having a second probe and completely covering another waveguide input so as to form a hermetic seal over said another waveguide input;   said first and second substrates constituting separate substrates; and   a first stub disposed on at least said first substrate; a second stub disposed on at least said first substrate; whereby said first and second stubs have been short-circuited for substantially matching the impedance between said first probe and said microstrip line.   
     
     
       2. The transition according to claim 1 wherein said transition is incorporated into a package containing one or more components selected from the group consisting of radio frequency components, microwave frequency components, and millimeter frequency components, said first and second probes being connected to said components for providing said signals to said components. 
     
     
       3. The transition according to claim 2 wherein said components include at least one integrated circuit chip for processing said signals from said first and second probes. 
     
     
       4. The transition according to claim 2 further comprising: a frame connected to said first substrate, said frame defining at least a portion of said cavity which contains said first probe, said frame defining at least a portion of a cavity which contains said second probe; and   said cover being fastened onto said frame.   
     
     
       5. The transition according to claim 1 further comprising: a base connected to said waveguide input and having a trough surrounding said waveguide input, said first substrate being insertable into said trough thereby forming said hermetic seal, said trough providing alignment of said first substrate with said base, said second substrate being separately insertable into said trough thereby forming said hermetic seal, said trough providing alignment of said second substrate with said base.   
     
     
       6. The transition according to claim 5 wherein said first and second substrates are eutectically soldered substrates with respect to said base for forming a hermetic seal with said base. 
     
     
       7. The transition according to claim 1 further comprising: a base, said first and seconds substrates are eutectically soldered substrates with respect to said base thereby forming said hermetic seal.   
     
     
       8. The transition according to claim 1 wherein said first and second probes are etched probes respectively upon said first and second substrates. 
     
     
       9. A waveguide-to-microstrip transition for processing electromagnetic wave signals comprising: a waveguide for directing said signals to a waveguide input;   a cover for forming at least a portion of a cavity over said waveguide input, said cover providing both a backshort and a seal for said transition;   a substrate connected to said waveguide input;   a probe disposed upon said substrate for conducting said signals to a microstrip line; and   an iris being substantially disposed in said cavity for providing isolation for said cavity, a first stub disposed on said substrate; a second stub disposed on said substrate; whereby said first and second stubs have been short circuited for substantially matching the impedance between said probe and said microstrip line .   
     
     
       10. The transition according to claim 9 further comprising: third stub disposed on said substrate;   whereby said first and second and third stubs have been short-circuited for substantially matching the impedance between said probe and said microstrip line.   
     
     
       11. The transition according to claim 10 wherein said first stub is connected to said probe, said second and third stubs are connected to said microstrip line. 
     
     
       12. The transition according to claim 10 wherein said substrate has a first side and a second side, said probe being etched onto the first side of said substrate, said iris being appended onto the second side of said substrate. 
     
     
       13. The transition according to claim 10 wherein the dimensions of said iris are determined so as to allow said transition to operate in a broadband capacity. 
     
     
       14. The transition according to claim 10 wherein said substrate overlaps said waveguide input thereby forming a hermetic seal, and wherein said probe is etched upon said substrate. 
     
     
       15. The transition according to claim 10 wherein said transition is incorporated into a package containing one or more components selected from the group consisting of radio frequency components, microwave frequency components, or millimeter frequency components. 
     
     
       16. The transition according to claim 15 wherein said components include at least one integrated circuit chip for processing said conducted signals from said microstrip line. 
     
     
       17. The transition according to claim 15 further comprising: a frame connected to said substrate, said frame defining a cavity which contains said probe;   a cover which is fastened onto said frame; and   a base having a trough which surrounds said waveguide input, said substrate being insertable into said trough thereby forming a hermetic seal between said base and said substrate, said substrate being eutectically soldered to said base to form a hermetic seal with said base.   
     
     
       18. A waveguide-to-microstrip transition for processing electromagnetic wave signals comprising: a waveguide for directing said signals to a waveguide input;   a cover for forming at least a portion of a cavity over said waveguide input, said cover providing both a backshort and a seal for said transition;   a substrate covering said waveguide input, said substrate being hermetically sealed to said waveguide;   a probe on said substrate and overlying said waveguide input;   an iris for providing isolation for said cavity, said iris being substantially disposed in said cavity;   a microstrip line which is connected to said probe;   a first stub disposed on said substrate; and   a second and third stub disposed on said substrate;   said first and second and third stubs having been short-circuited for substantially matching the impedance between said probe and said microstrip line;   said first stub being connected to said probe, said second and third stubs are connected to said microstrip line.